Tumor Necrosis Factor alpha or TNFα, is a pro-inflammatory cytokine secreted by a variety of cells, including monocytes and macrophages, in response to many inflammatory stimuli or external cellular stress. It is a key cytokine in the inflammation cascade causing the production and/or release of other cytokines and agents.
Excessive or unregulated TNFα production has been implicated in mediating or exacerbating a number of disease states. Decreasing TNFα levels thus constitutes a valuable therapeutic strategy for the treatment of many inflammatory, infectious, immunological or malignant diseases. Collectively such disorders may be grouped as “immunoinflammatory maladies.” These “immunoinflammatory maladies” include, but are not restricted to rheumatoid arthritis, Paget's disease, osteoporosis, multiple myeloma, uveititis, acute and chronic myelogenous leukemia, pancreatic β cell destruction, rheumatoid spondylitis, gouty arthritis, inflammatory bowel disease, adult respiratory distress syndrome (ARDS), psoriasis, Crohn's disease, allergic rhinitis, ulcerative colitis, anaphylaxis, asthma, muscle degeneration, cachexia, Reiter's syndrome, type I and type II diabetes, bone resorption diseases, graft vs. host reaction, ischemia reperfusion injury, atherosclerosis, brain trauma, multiple sclerosis, cerebral malaria, sepsis, septic shock, toxic shock syndrome, fever, and malgias due to infection.
TNFα appears to be involved in bone resorption diseases, including arthritis. In rheumatoid arthritis, TNFα induce synoviocytes and chondrocytes to produce collagenase and neutral proteases, which leads to tissue destruction within the arthritic joints.
It has been reported that TNFα plays a role in head trauma, stroke and ischemia. The TNFα levels increased in the contused hemisphere in rat models of head trauma (Shohami et al., J. Cereb. Boold Flow Metab. 14, 615 (1994)).
TNFα also plays a role in the area of chronic pulmonary inflammatory diseases. The deposition of silica particles leads to silicosis, a disease of progressive respiration failure caused by a fibrotic reaction.
TNFα blockage has been shown to be beneficial in rheumatoid arthritis and other diseases (Elliot et al., Int. J. Pharmac. 17(2), 141 (1995), Pisetsky, N. Engl. J. Med. 342(11), 810-1 (2000)). Several approaches have been taken to block the effect of TNFα. One approach involves using soluble receptors for TNFα, which have demonstrated efficacy in animal models of TNFα mediated disease states. Enbrel®, a solublized TNFα receptor, has shown efficacy against moderately to severely active rheumatoid arthritis and has been approved for use in those patients who have an inadequate response to one or more disease-modifying anti-rheumatic drugs. A second approach is to neutralize TNFα using a monoclonal antibody specific to TNFα. For instance, a TNFα-binding chimerical monoclonal antibody, Remicade™, has demonstrated improvement in swollen joint count in a human trial of rheumatoid arthritis and marked in conjunction with methotrexate for the treatment of patients with rheumatoid arthritis who have had an inadequate response to methotrexate alone. Suppression of the effects of TNFα has also been achieved through the utilization of steroids such as dexamethasone and prednisolone in the early experiments (Beutler et al., Science 234, 470-474 (1985); WO 92/11383).
High levels of TNFα are associated with Crohn's disease (von Dullemen et al., Gastroenterology 109, 129 (1995)) and clinical benefit has been achieved with TNFα antibody treatment. The TNFα-binding chimerical monoclonal antibody, Remicade™, has also been approved for use in treatment of Crohn's disease patients.
The transcription factor Nuclear Factor kB (NFkB) has been shown to regulate the production of many proinflammatory cytokines including but not limited TNFα and related proteins that are elevated in immunoinflammatory diseases (Grilli et al., Int. Rev. Cytol. 143, 1-62 (1993)). The TNFα level and transcription activity of NFkB are influenced by a reciprocal feedback loop. The compounds described in this invention affect both the TNFα level and transcription activity of NFkB. NFkB has been shown to play a role in diseases including osteoarthritis, transplant rejection, ischemia, reperfusion injury, trauma, certain cancers and viral disorders, and autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, psoriasis, inflammatory bowel disease, glomerulonephritis, lupus and juvenile diabetes.